1. Field of the Invention
The present invention relates to a room temperature curable organopolysiloxane composition which cures easily in the presence of moisture in air to become a rubber-like elastic material, and more particularly to a room temperature curable organopolysiloxane composition having excellent mildewproofing properties.
2. Description of the Prior Art
Heretofore, room temperature curable organopolysiloxane compositions which cure easily in the presence of moisture to form a rubber-like elastic material have been used for a wide range of applications such as adhesive, coating material, electrically insulating sealing material, constructional sealing material, etc. This type of compositions, however, have the disadvantage that in a long-term use thereof, the appearance of their cured products is damaged due to propagation of fungi deposited on the surface thereof.
In order to prevent the deposition and propagation of fungi, a number of methods have been known for controlling the propagation of fungi by adding a mildewproofing agent to the compositions of the above type. For example, there have been known a method by addition of 2,3,5,6-tetrachloro-4-methylsulfonylpyridine (Japanese Pre-examination Patent Publication (KOKAI) No. 51-106158 (1976)), a method by addition of 2-(4-thiazolyl)benzimidazole (Japanese Pre-examination Patent Publication (KOKAI) No. 54-127960 (1979)), a method by addition of an N-substituted benzimidazolyl carbamate derivative (Japanese Pre-examination Patent Publication (KOKAI) No. 56-38348 (1981)), a method by addition of a germicide having the following general formula: EQU R--Ph--SO.sub.2 --C(R').sub.2 --I
wherein R is a hydrogen atom, a halogen atom or an alkyl group of from 1 to 4 carbon atoms, and R' is a hydrogen atom, an iodine atom or an alkyl group of from 1 to 4 carbon atoms (Japanese Pre-examination Patent Publication (KOKAI) No. 56-127658 (1981)), a method by addition of triorganotin compound (Japanese Pre-examination Patent Publication (KOKAI) Nos. 56-133150 (1981) and 57-96044 (1982)), a method by addition of benzimidazolyl alkyl carbamate (Japanese Pre-examination Patent Publication (KOKAI) No. 60-18693 (1985)), a method by addition of tetraalkylthiuram disulfide (Japanese Pre-examination Patent Publication (KOKAI) No. 60-115660 (1985)), and so on.
However, the conventional methods are limited in the kind of fungi whose propagation can be prevented. In addition, according to the conventional methods it has been difficult to maintain the mildewproofing effect for a long time.